1. Field of the Invention
The invention relates to an axial piston machine.
Such axial piston machines are known in practice. In particular with swash plate machines, the normal force supporting each piston at the swash plate contains a radial component which acts upon the piston as on a beam mounted in the cylinder drum and skewing the piston within the cylinder. In particular with a lack of piston lubrication, such as occurs for example during the start-up phase, this leads to metallic contact between piston and cylinder wall with the consequence of corresponding heating through the frictional forces arising, and the danger of seizing of the piston.
2. Discussion of the Prior Art
From DE-OS 14 03 754 there is known an axial piston machine with which, for the purpose of avoiding the metallic contact between piston and cylinder, there are formed at the periphery of each cylinder or of the associated piston symmetrically formed pressure pockets which are connected via respective chokes and axial through-bores in the piston with the working chamber of the cylinder. The piston is lubricated and hydrostatically balanced by means of the oil, under high pressure, flowing into the pressure pockets from the working chamber during the compression stroke, and in this way the piston is centrally guided in the cylinder without the danger of skewing. The quantity of oil necessary for the hydrostatic balancing is absent from the working circuit of the axial piston machine and thus leads to a reduction of the efficiency of the machine.
The axial piston motor described in DE-OS 18 04 529 has the same advantages and disadvantages, in which axial piston motor there is formed in the wall of each cylinder a circumferential groove which is connected via connection channels in the cylinder drum and in the connection block to the high pressure line of an axial piston pump driving this axial piston motor.
It is the object of the invention to so further develop an axial piston machine of the kind mentioned in the introduction that while maintaining the efficiency of the machine, seizing of the pistons in the cylinders is avoided.